Best Food: Plain or Greek Yogurt

We all know that yogurt is good for us, but did you know it's also good for maintaining your flat abs? For a nice mid-section, nutritionist and owner of Essential Nutrition For You Rania Batayneh says to reach for the kind that's plain flavored or Greek. “The probiotic bacteria in most yogurts help keep your digestive system healthy, which translates into a lower incidence of gas, bloating, and constipation, which can keep your tummy looking flat." (And it's not just for breakfast! Check out these 7 Ways to Enjoy Greek Yogurt for Lunch.)

Worst Food: Refined Carbs

Stay away from white flours and white rice because they get digested very quickly, causing spikes in both insulin and blood sugar levels, Palinski says. "This increased level of insulin in our body can promote increased fat storage in the abdominal area," she adds. (Instead try any of these 8 New Types of Flour.)

Best Food: Whole Grains

Set aside the white bread and rice and swap them in for whole grains such as 100-percent whole wheat bread, lentils, and brown rice. “A recent study in the American Journal of Clinical Nutrition showed that a calorie-controlled diet rich in whole grains trimmed extra fat from the waistline of obese subjects," Palinski says. “This may be due to the decreased insulin response to whole grains versus refined carbohydrates, making it easier to mobilize fat storage."

Worst Food: Salty Foods

Ever wonder why you feel extra bloated after eating sushi with a lot of soy sauce? Eating foods high in sodium can lead to fluid retention. "When we are retaining fluid, the fluid often causes our belly to look puffier and bloating, masking your flat abs. Aim to consume less than 2000 mg [of sodium] per day," Palinski says.

Photo: Corbis Images

Best Food: Monounsaturated Fats

New research indicates that a diet high in monounsaturated fats like olive oil can help us lose some of that belly fat, even without changing calorie intake or adding in additional exercise, Palinski says.

Photo: Corbis Images

Best Food: Vinegar

A Japanese study found that the substance that gives vinegar its sour taste and strong odor might fight fat. "The study found that in overweight individuals who consumed 1 or 2 tablespoons of apple cider vinegar daily for 12 weeks had significantly lower body weight, BMI, visceral (belly) fat, and waist circumference than the control group that didn't consume any vinegar," Palinski says. “Researchers feel this may be due to vinegar's acetic acid, which may switch on genes that pump out proteins that break down fat." (ACV is not just for weight loss! Learn the 7 Health Benefits of Drinking Apple Cider Vinegar.)